. >>> the pentagon has grounded its new fleet of 51 f-35 fighter jets is after a crack was found in the engine blade of one plane. all of the planes are being tested at the time. none were being used in combat. it's the pentagon's most sophisticated aircraft system and the most expensive, costing almost 4$4 billion. >>> the first lady's efforts to encourage young people to exercise got some support from jimmy fallon. he teamed up with the first lady. there you see it to perform the evolution of mom dancing. fallon asked mrs. obama if she would consider running on the presidential ticket with hillary clinton in 2016. the first lady said she was interested in another job, hosting for "the tonight show" when jay leno retires. she's quick. >> she is quick. >>> here's stacy-ann gooden with a look at the weather. good morning. >> good morning. we're looking at pretty active conditions out west. i know it doesn't look like that, but we want to point your attention to what's going on out across the northeast. this system has been dumping heavy rainfall across much of the gulf states and trekkin